The main problem with testing candidate analgesics, drugs for pain relief, is that patients respond to them differently, even when patients have identical diagnostic classifications.

Because candidate drugs are generally not tested specifically for certain aspects of pain in early clinical studies, promising drugs may be disregarded. In this project the effects of new pain medication, with respect to these different aspects, in healthy subjects and in well-characterized subgroups of patients are studied for the first time. The subgroups are selected from a unique database consisting of sensory details of 300 chronic pain patients. The specific subgroups of patients are further studied using fMRI, which is an objective method that enables the study of pain-related processes in the brain, separated from a persons' emotional and cognitive state. This way, only a small number of patients or healthy volunteers are needed to demonstrate whether a new candidate analgesic is effective for a large number of patients.

Background

Pain is a multi-dimensional phenomenon which we are all familiar with. Tissue damage leads to acute pain, but damaged nerves are responsible for certain chronic types of pain called neuropathic pain. In this case pain signals continuously fire in the nervous system. Chronic pain may result from an unfortunate accident, such as a sprained back, or an ongoing cause of pain such as amputation, cancer, diabetes or shingles. Some people even experience chronic pain without a clear cause being identified. According to the Pain Platform, around three million people in the Netherlands alone suffer from chronic pain, mostly adults, of which two million are experiencing pain for more than 7 years. More than 40% of the chronic pain patients in the Netherlands have never received sufficient and adequate pain killers. In the long run chronic pain may cause other symptoms and conditions such as depression or anxiety. Although to date little research has been conducted, chronic pain is believed to have cognitive effects, especially a reduced ability to perform attention-demanding tasks.